Tobacco use continues to be one of the leading, preventable causes of morbidity and morbidity in the United States and primary care clinicians are in a unique position to provide brief advice to a large portion of the population. The 5As framework (ASK, ADVISE, ASSESS, ASSIST, ARRANGE) is recommended for brief smoking cessation counseling in the primary care context. Systematic reviews indicate a moderate positive association between counseling based on the 5As and abstinence from smoking; however most 5A assessments rely on clinician recall, patient recall or medical record review that may lead to over or under-reporting of actual clinician behavior. Further, there is little dat to elucidate the effect of the completeness and appropriate sequence of delivery of the 5As on patient outcomes. Accurately measuring the impact of low intensity interventions, like brief clinician advice based on the 5As framework, requires a patient outcome measure that is reliable, sensitive to change, applicable to the full spectrum of patient level of readiness for smoking cessation and associated with smoking abstinence. Our study team has developed two innovative measures to address these methodologic challenges. First, we developed the 5As Direct Observation Coding scheme (5A-DOC) that uses clinician-patient talk to determine the degree to which each of the 'A's are accomplished. The 5A-DOC is reliable, valid and advice can be classified with regard to completeness and appropriate sequencing of delivery of the 'A's. Second, using Rasch analysis we developed an innovative measure of Incremental Behavior Change for smoking cessation (IBC- S).This measure is reliable, sensitive to change and associated with smoking cessation. By pooling data from the initial sample of 131 cases used to develop the 5A-DOC with a new study, we can apply the 5A-DOC to 774 cases across 59 primary care clinicians and test associations with smoking cessation-related outcomes using multilevel modeling with adequate power. Patient outcomes, including the IBC-S, are parallel across both studies. A subsample of patients in Study 2 completed a survey assessing receipt of each 5A element such that we can compare patient report to the 5A-DOC. We have a compelling opportunity to examine the following research questions: What is the effect of complete delivery of the 5A elements on intermediate patient outcomes (i.e. patient recall of the advice, incremental behavior change, reduction in the number of cigarettes, and reported smoking cessation)? What is the effect of the sequence of delivery of the 5A elements on intermediate patient outcomes? How accurate are patient reports of the 5A elements compared to a direct observation coding system? This work is important to researchers assessing the 5As, educators of clinicians and ultimately can impact the efficiency and effectiveness of cessation advice in the primary care setting.